Traditionally, transportation and related services have been provided by a human-operated vehicle. Improvements in computer processing have led to increasing efforts to automate more of these services, using autonomous vehicles that do not require a human operator. However, integrating these autonomously-provided services into a mixed autonomous and human-operated environment has many challenges. Drivers and pedestrians are accustomed to interacting in particular ways, removing a driver from some vehicles can lead to uncertainty and miscommunication.